For the ventilation of a volume with a rectangular cross section of 2. 2m m x 2. 2m and a length of 4.24 m two ventilation concepts have been tested. The first one uses only the velocity of the air blown through the air inlet diffusers into the volume, whereas for the second one additional fans are installed within the volume. They are used to accelerate the air contained in the volume.None of the two investigated solutions fulfils the stringent air velocity requirements (0.08 m/s ≤ W ≤ 0.2 m/s) throughout the whole volume completely.